Kata kunci ialah perkataan yang mempunyai beberapa makna. Dalam penggunaan biasa bahasa PHP, perkataan ini tidak boleh digunakan sebagai pemalar, nama pembolehubah, nama kaedah, nama kelas, dll. Kata kunci ini apabila digunakan secara automatik difahami oleh PHP. Kata kunci PHP ini, apabila digunakan dengan nama pembolehubah, boleh dikelirukan dengan kata kunci sebenar. Oleh itu, kata kunci ini tidak boleh digunakan sebagai nama pembolehubah.
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Berikut ialah senarai:
Kod:
<?php //example to demonstrate abstract keyword abstract class Program { abstract protected function MethodOne(); public function display() { echo '<br>'.$this->MethodOne(); } } class ProgramOne extends Program { protected function MethodOne() { echo '<br>'.'In MethodOne'; } } $objOne = new ProgramOne; $objOne->display(); ?>,
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Kod :
<?php //example to demonstrate and keyword $a = 10; $b = 11; if($a ==10 and $b == 11) { echo 'Result : True'; } else { echo 'Result : False'; } ?>
Output:
Kod:
<?php //example to demonstrate array keyword $directions = array("e" => "east", "w" => "west", "n" => "north", "s" => "south"); print_r($directions); ?>
Output:
Kod:
<?php //example to demonstrate array keyword $directions = array("e" => "east", "w" => "west", "n" => "north", "s" => "south"); foreach($directions as $key=>$value) { echo '<br>'. $key. '=>'.$value; } ?>
Output:
Kod :
<?php //use of break keyword without optional argument $arr = array("water", "sky", "try", "sand"); foreach($arr as $key=>$value) { if($value == 'try') { break ; // can use break 1 also } echo '<br>'.$value; } ?>
Output:
Kod:
<?php //example to demonstrate case keyword $i = 1; while($i<5) { switch($i) { case 1: echo "<br>"."One"; break; case 2: echo "<br>"."Two"; break; case 3: echo "<br>"."Three"; break; default: echo "<br>"."Default"; } $i++; } ?>
Output:
Kod:
<?php //example to demonstrate catch keyword function Operation() { try { $num1 = 10; $num2 = 0; if($num1 / $num2) { throw new Exception('Divide By Zero'); } } catch (Exception $e) { die($e->getMessage()); } } Operation(); ?>
Output:
Kod:
<?php //example to demonstrate class keyword class ClassOne{ var $str = 'Hello World'; public function displayMethod() { echo $this->str; } } $obj = new ClassOne; $obj->displayMethod(); ?>
Output:
kata kunci const digunakan untuk mentakrifkan nama dengan nilai menggunakan operator tugasan seperti di bawah
UMUR konst= 29;
Tiada tanda $ pada permulaan nama tetap seperti pembolehubah biasa.
Kod:
<?php // example to demonstrate default keyword $fruits = 'Cherries'; switch ($fruits) { case 'Apple': echo "Apple"; break; case 'Banana': echo "Banana"; break; case 'Papaya': echo "Papaya"; break; default: echo "Fruit is not Apple, Banana or Papaya "; break; } ?>
Output :
Kod:
<?php // example to demonstrate do keyword $x = 2; do { if($x > 2) { echo 'x is greater than 2'; } else{ echo 'x is less than 2'; } } while ($x < 2); ?>
Output:
Kod :
<?php //example to demonstrate die keyword $conn = mysqli_connect('localhost','root','','dbname'); if(!$conn) { die("Unable to connect "); } ?>
Output:
Kod:
<?php // example to demonstrate echo keyword echo 'Hello! '; $name = 'John Doe'; echo 'My name is '. $name; ?>
Output:
Kod:
<?php // example to demonstrate else keyword $a = 10; if ($a > 5) { echo "a is greater than 10"; } else { echo "a is not greater than 10"; } ?>
Output:
Kod:
<?php // example to demonstrate elseif keyword $a = 10; if ($a > 10) { echo "a is greater than 10"; } elseif ($a == 10) { echo "a is equal to 10"; } else { echo "a is smaller than 10"; } ?>
Output :
Kod:
<?php // example to demonstrate empty keyword $str = 'Hello World!'; if(empty($str)) { echo 'Variable is empty'; } else { echo $str; } ?>
Output:
Kod:
<?php // example to demonstrate endfor keyword for($i=0;$i<5;$i++) : echo "<br/>".$i; endfor; ?>
Output:
Kod :
<?php // example to demonstrate endif keyword if ($a > 10): echo "a is greater than 10"; elseif ($a >10) : echo "a is equal to 10"; else: echo "a is not equal to 10"; endif; ?>
Output:
Kod:
<?php // example to demonstrate endforeach keyword $arr = array(1,2,3,4,5,6,7,8,9,10); foreach ($arr as $key=>$value): echo '<br>'.$value; endforeach; ?>
Output:
Kod:
<?php // example to demonstrate endswitch keyword $fruits = 'Cherries'; switch ($fruits): case 'Apple': echo "Apple"; break; case 'Banana': echo "Banana"; break; case 'Papaya': echo "Papaya"; break; default: echo "Fruit is not Apple, Banana or Papaya "; break; endswitch; ?>
Output:
Kod:
<?php // example to demonstrate endwhile keyword $i = 0; while($i<5): echo "<br>".$i; $i++; endwhile; ?>
Output:
Code:
<?php //example to demonstrate eval keyword $string1 = 'World'; $string2 = 'John Doe'; $string = 'Hello $string1 . My name is $string2'; echo "<br>".$string; eval("\$string = \"$string\";"); echo "<br>".$string; ?>
Output:
This keyword when encountered in a script, terminates the execution of the script.
Code:
<?php //example to demonstrate extends keyword class ParentClass { var $string = 'PHP'; public function display() { echo $this->string; } } class ExtendClass extends ParentClass { public function display() { echo 'Hello World!'; } } $obj1 = new ExtendClass; $obj1->display(); ?>
Output:
Code:
<?php //example to demonstrate final keyword class ParentClass { var $string = 'PHP'; final public function display() { echo $this->string; } } class ExtendClass extends ParentClass { public function display() { echo 'Hello World!'; } } $obj1 = new ExtendClass; $obj1->display(); ?>
Output :
Code:
<?php //example to demonstrate catch keyword try { $num1 = 10; $num2 = 0; if($num1 / $num2) { throw new Exception('Divide By Zero'); } } catch (Exception $e) { echo '<br>'.$e->getMessage(); } ?>
Output:
Code:
<?php // example to demonstrate for keyword for($i=0; $i<10; $i++) { if($i == 5) { break; } echo '<br>'.$i; } ?>
Output :
Code:
<?php // example to demonstrate foreach keyword $array = array(10,20,30,40,50); foreach($array as $value) { echo '<br>'.$value/10; } ?>
Output:
Code:
<?php function calSum($a , $b) { $c = $a + $b; return $c; } $result = calSum(10 , 20); echo '<br> The sum : '.$result; ?>
Output:
Code:
<?php //example to demonstrate global keyword $a = 10; $b = 20; function fun() { global $a; global $b; $result = $a + $b; return $result; } $f = fun(); echo 'The result is '.$f; ?>
Output:
Code:
<?php // example to demonstrate if keyword $sum = 10; if($sum == 10) { echo 'Sum is 10'; } else { echo 'Sum is not 10'; } ?>
Output:
Code:
<?php //example to demonstrate interface keyword interface One { public function first(); } class MainClass implements One { public function first() { echo 'This is the First function'; } } $obj = new MainClass; echo $obj->first(); ?>
Output :
Code:
file.php
<?php //example to demonstrate include keyword $a = 'The Earth'; $b = 'Round'; ?>
index.php
<?php include 'file.php'; echo $a . ' is '. $b. ' in Shape'; ?>
Code:
file.php
<?php //example to demonstrate include_once keyword $a = 'The Earth'; $b = 'Round'; ?>
index.php
<?php Include_once 'file.php'; echo $a . ' is '. $b. ' in Shape'; ?>
Output:
Code:
<?php //example to demonstrate instanceOf keyword class MainClass { public function MainCLassMethod(){ echo 'Hello World!'; } } class ExtendedClass extends MainClass { public function ExtendedClassMethod(){ echo 'Have a Nice Day!'; } } $obj1 = new ExtendedClass; var_dump($obj1 instanceOf ExtendedClass); ?>
Output:
Code:
<?php //example to demonstrate interface keyword interface One { public function one(); } interface Two { public function two(); } class MainClass implements One, Two { public function one() { echo '<br> This is the one function'; } public function two() { echo '<br> This is the two function'; } } $obj = new MainClass; echo $obj->one(); echo $obj->two(); ?>
Output:
Code:
<?php //example to demonstrate isset keyword $stringOne = ''; var_dump(isset($stringOne)); $stringTwo = NULL; var_dump(isset($stringTwo)); ?>
Output :
Code:
<?php //example to demonstrate list keyword $names = array('Ram','Mohan','Raghav'); list($person1, $person2, $person3) = $names; echo "$person1, $person2 and $person3 are friends"; ?>
Output:
Code:
<?php //example to demonstrate new keyword class Student { public function score($name, $subject, $marks) { echo "$name scored $marks marks in $subject"; } } $obj = new Student; $obj->score('Sunil','Maths',90); ?>
Output:
Code:
<?php //example to demonstrate or keyword $a = 10; $b = 11; if($a ==10 or $b == 12) { echo 'Result : True'; } else { echo 'Result : False'; } ?>
Output :
Code:
<?php //example to demonstrate print keyword $str = "PHP Programming"; print($str); $stringOne = "Shyam, "; $stringTwo = "How are you?"; print "<br>"."Hello $stringOne $stringTwo"; ?>
Output :
Code:
<?php //example to demonstrate private keyword class MainClass { private $str = 'Private'; function PrivateMethod() { echo 'In '. $this->str. ' Method'; } } $obj = new MainClass(); $obj->PrivateMethod(); //Shows Private Method ?>
Output:
Code:
<?php //example to demonstrate public keyword class MainClass { public $str = 'Public'; function PublicMethod() { echo 'In '. $this->str. ' Method'; } } $obj = new MainClass(); $obj->PublicMethod(); //Shows Public Method ?>
Output:
Code:
<?php //example to demonstrate protected keyword class MainClass { protected $str = 'Protected'; function ProtectedMethod() { echo 'In '. $this->str. ' Method'; } } $obj = new MainClass(); $obj->ProtectedMethod(); //Shows Protected Method ?>
Output:
Code:
<?php //example to demonstrate return keyword function sum() { $a = 10; $b = 20; $c = $a +$b; return $c; } $result = sum(); echo 'Sum : ' . $result; ?>
Output:
Code:
<?php //example to demonstrate switch keyword $i= 3; switch($i) { case 1: echo "<br>"."One"; break; case 2: echo "<br>"."Two"; break; case 3: echo "<br>"."Three"; break; default: echo "<br>"."Default"; } ?>
Output:
Code:
<?php //example to demonstrate throw keyword function division($x, $y) { try { if($y == 0) { throw new Exception('Divide By Zero'); } } catch (Exception $e) { echo '<br>'.$e->getMessage(); } } division(10,0); ?>
Output:
Code:
<?php //example to demonstrate try keyword try{ $arr = array(); $arr_length = count($arr); if($arr_length == 0) { throw new Exception('Error : Empty Array!'); } else { echo 'Array found'; print_r($arr); } } catch(Exception $e) { echo '<br>'.$e->getMessage(); } ?>
Output:
Code:
<?php //example to demonstrate unset keyword echo 'Hello World!'.'<br>'; $a = 10; echo $a; unset($a); // echo $a; //this line when uncommented shows error : Undefined variable, as the variable is unset ?>
Output:
Code:
<?php //example to demonstrate var keyword class MainClass { var $str = 'PHP Programming'; public function displayMsg() { echo $this->str; } } $obj = new MainClass; $obj->displayMsg(); ?>
Output:
Code:
<?php //example to demonstrate while keyword $i = 0; while ($i<10) { echo '<br>'. $i; $i++; } ?>
Output:
In this article, you will learn about keywords in PHP with examples. These examples explain the usage of each of the keyword in PHP.
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